In-situ exfoliation and assembly of 2D/2D g-C3N4/TiO2(B) hierarchical microflower: Enhanced photo-oxidation of benzyl alcohol under visible light

This study demonstrates the successfully fabrication of 2D/2D g-C3N4/TiO2(B) hierarchical microflowers via a hydrothermal in-situ exfoliation and assembled method. The structural and optical properties of g-C3N4/TiO2(B) are characterized by X-ray diffraction, transmission electron microscopy, as well as spectroscopic techniques. The recombination of g-C3N4 with TiO2(B) significantly improves the photocatalytic performance in the photooxidation of benzyl alcohol to benzaldehyde using visible light (lambda > 420 nm). Trapping experiments and electron spin resonance spectroscopy indicate the active radicals of center dot O-2(-), center dot OH and h(+) are responsible for the enhanced activity. The heterojunction interface between g-C3N4 sheets and TiO2(110) facets boosts separation efficiency of photogenerated charges, thus resulting into the high catalytic performance of g-C3N4/TiO2(B) composites. Density functional theory (DFT) calculations reveal that the charge transfer between the TiO2(B) and g-C3N4 interface and the consequent formation of a built-in electric field at the interface, which are responsible for the high catalytic performance of g-C3N4/TiO2(B) composites. The study firstly reports a simple in-situ hydrothermal growth protocol to efficiently construct 2D/2D g-C3N4/TiO2(B) heterojunction composites and offer guidelines for design of a new synthetic strategy to prepare efficient photocatalysts.